1.In Vitro Antagonism of Phytophthora capsici And Fusarium solani by Bacterial Isolates from Sarawak
Mohd Farith Kota ; Awang Ahmad Sallehin Awang Husaini ; Samuel Lihan ; Mohd Hasnain
Malaysian Journal of Microbiology 2015;11(2):135-143
Aims: Phytophthora capsici and Fusarium solani are common fungal pathogens causing severe diseases that lead to
economic loss in pepper industry, especially in Sarawak. In response to the infections, chemical approach is more
common; nevertheless, biological control is more favorable to control fungal pathogens. Biological control approach
greatly reduces the problems associated with chemical applications and it restores balance of the natural environment.
Here we present the ongoing work to study the action of antagonistic bacteria, Bacillus sp. and Pseudomonas sp., that
produce volatile and non-volatile antifungal compounds against P. capsici and F. solani on pepper plants.
Methodology and results: A total of seven bacterial candidates were isolated from different locations and tested for
their antagonistic properties against P. capsici and F. solani in a dual culture assay and extracellular metabolite test.
Extracellular hydrolytic enzymes production was also monitored and followed by genotypic indentification. Preliminary
antagonism tests indicated that bacterial isolate Pep3 and Pep4 inhibit up to 50% of the growth of P. capsici and F.
solani as compared to the control. Subsequent investigation on extracellular hydrolytic enzyme production revealed that
both bacterial isolates are capable of secreting hydrolytic enzymes. Microscopic and genotypic analyses identified the
bacterial isolates Pep3 as Bacillus amyloliquefaciens (KJ461444) and Pep4 as Pseudomonas pachastrellae
(KM460937).
Conclusion, significance and impact of study: B. Amyloliquefaciens (KJ461444) and P. pachastrellae (KM460937)
inhibited the growth of P. capsici and F. solani thus reflecting the potential of the produced metabolites to be purified and
used in combating plant pathogenic fungi.
Biological Control Agents
;
Fungi
;
Antibiosis
2.Factors affecting toxic lead(Ii) ion bioremediation by Fusarium equiseti isolated from the mangrove soil environment of southeast Borneo.
Wahab Abideen Akinkunmi ; Awang Ahmad Sallehin Awang Husaini ; Azham Zulkharnain ; Tay Meng Guan ; Hairul Azman Roslan
Malaysian Journal of Microbiology 2015;11(2):215-222
Aims: Electronic waste (e-waste) is an inorganic pollutant which causes a serious environmental problem since it
contains toxic heavy metals, which cannot be removed from contaminated sites easily. The use of biomaterials for
removing heavy metals from contaminated soil and wastewater has emerged as a potential alternative method to the
conventional techniques. The present study were aimed to isolate efficient lead tolerant fungi from mangrove soil
environment and measure its capability for lead removal from aqueous solution.
Methodology and results: Lead tolerant fungal strains were isolated from soil samples using PDA (Potato Dextrose
Agar) supplemented with varied concentrations of lead ions (100-500 mg/L). The most tolerant fungal strain was
successfully isolated and identified molecularly as Fusarium equiseti KR706303. The isolated fungus was used for
biosorption studies using Potato dextrose broth (PDB) supplemented with lead ions. The effects of pH, temperature,
initial metal concentration, biomass dose and age, agitation and contact time to the Pb(II) removal efficiency were
monitored in the study. The results showed that the optimal parameters for the removal of lead ions such as heavy metal
concentration and pH were 300 mg/L, with a maximum Pb(II) adsorption of 97.9% observed at pH 4 and temperature of
30 °C during the batch biosorption experiments. The optimal parameters for biomass dose, agitation speed, contact time
and biomass age were observed at 0.04 g, 150 rpm, 60 min and fifth day; respectively.
Conclusion, significance and impact of study: The observation in this study revealed that the biomass of the isolated
Fusarium equiseti KR706303 has the potential to be used as a biosorbent for heavy metal particularly Pb(II) removal
from the contaminated sites. The technology is simple, efficient, cost effective and environmental friendly.
Electronic Waste
;
Metals, Heavy
;
Hazardous Waste
3.Antimicrobial, total phenolic and total flavonoid properties of leaves and seed of Jatropha curcas, Piper nigrum L. and Piper betle methanolic crude extracts
Mohamad Iswandy Ibrahim ; Awang Ahmad Sallehin Awang Husaini ; Noorzaid Muhamad ; Hairul Azman Roslan
Malaysian Journal of Microbiology 2016;12(6):438-444
Aims: Herbal and medicinal plants bioactive compounds of Jatropha curcas, Piper nigrum and P. betle have been
shown to possess therapeutic properties. This study investigates the presence and characterization of phytochemical
compounds as well as to evaluate the antimicrobial activities of the methanolic crude extract of the leaves and seeds of
J. curcas, P. nigrum L. and P. betle.
Methodology and results: The study on antibacterial and antifungal efficacy of the crude extracts of leaves and seeds
were carried out using standard disc diffusion method. The crude extracts were found to exhibit an average response of
antimicrobial activity with the inhibition zones ranged from 3% to 28% for antibacterial and from 21% to 79% for
antifungal activity. Among all extracts, the leaf extract of P. betle showed a good antibacterial activity against
Staphylococcus aureus and excellent antifungal properties against Aspergillus niger and A. flavus. The phytochemical
screening analysis revealed the presence of saponin, tannins, glycosides, terpenoids, reducing sugar, flavonoid and
anthraquinones. However, phlobatannins was not present. Total phenolic content (TPC) and total flavonoid content
(TFC) were highly detected in the crude extract of P. betle and recorded as 13.33 mg of gallic acid equivalents, GAE
(mg/ 100 mg sample) and 0.88 mg of RE (mg/100 mg sample), respectively. GC-MS analysis of the bioactive
compounds reveals the presence of diethyl phthalate, 2-hexadecen-1-ol (Phytol), hexadecanoic acid, piperine, phenol
and other minor compounds.
Conclusion, significance and impact of study: The study suggested that P. betle has a potential as a source for
antimicrobial agent from plants extracts. Nevertheless, further studies are needed to elucidate their precise mechanism
of action.
Therapeutics